About this replacement
Garmin GPSMAP 276Cx — 3.7V Li-ion Replacement Battery (010-12456-06)
This is a 3.7V, 6800mAh Li-ion cell built to fit the Garmin GPSMAP 276Cx portable GPS navigator. It replaces OEM part numbers 010-12456-06 and 361-00092-00. The 276Cx is a marine and wilderness navigation unit — this battery restores full power to that platform.
- GPSMAP 276Cx platform fit: The 276Cx uses a single-cell 3.7V pack with a specific connector pinout and BMS handshake. This cell matches that configuration — voltage rail, physical dimensions (74.70 × 42.70 × 21.75mm), and connector orientation all align with the OEM slot.
- Bench tested on actual hardware: We cycled this cell through charge and discharge on the GPSMAP 276Cx platform. The BMS accepted the cell without error flags, charge terminated cleanly at full voltage, and the unit powered on normally across multiple cold-start cycles.
- Cold-start satellite acquisition after fitting: After any full power interruption — including a battery swap — the 276Cx performs a GPS cold start. Power the unit on outdoors in open sky and let it run. First satellite fix typically takes 5–10 minutes. Subsequent warm starts drop to under a minute once almanac data rebuilds.
GPS accuracy reduced when battery charge drops below 20%
The GPSMAP 276Cx scales back receiver sensitivity at low battery to reduce power draw. This shows up as increased position error or slower track updates on the map screen. It is not a hardware fault — it is a firmware-level power management response. Keep charge above 20% during active navigation to hold full receiver performance.
Device shuts off without warning before the battery indicator reaches empty
After a battery swap, the 276Cx voltage-to-percentage curve is uncalibrated against the new cell. The unit reads remaining capacity from cell voltage, and if the old calibration curve does not match the new cell's discharge profile, the low-battery warning triggers late. The unit then hits the hardware cutoff voltage before the visual indicator catches up. Run two to three full charge and discharge cycles to let the firmware recalibrate — cutoff should stabilise at 3.0V per cell after that.